1. Field of the Invention
The present invention relates to a method of manufacturing a solar cell module including a plurality of solar cells sealed between a first protective member and a second protective member by using a sealing member that includes a first sealing member having a first melting point and a second sealing member having a second melting point, the second melting point higher than the first melting point, and to the solar cell module thus manufactured.
2. Description of the Related Art
Solar cells are expected as a new energy source that can directly convert clean and inexhaustibly supplied sunlight into electricity.
In general, each solar cell can output an energy of several watts. Accordingly, as a power source for a house, a building or the like, it is common to use a solar cell module that includes a plurality of solar cells connected to one another in order to provide enhanced energy output.
A solar cell module includes a solar cell string sealed between a light-receiving-surface-side protective member and a back-surface-side protective member. Here, the solar cell string indicates a plurality of solar cells connected to one another by using a wiring member.
Conventionally, a concept of sealing the solar cell string by use of two sealing members having different properties has been known.
For example, Japanese Patent Application Publication No. 2006-278740 discloses a sealing member for sealing a solar cell string having a laminated structure in which a first sealing member and a second sealing member are laminated. Here, the melting point of the first sealing member and the melting point of the first sealing member are different. This structure makes it possible to suppress a deterioration of an electrical insulation, on the light-receiving surface or the back surface of the solar cell string, due to a convex portion formed by a wiring member.
In general, sheet-shaped resin members are used as the first sealing member and the second sealing member. In a typical method of manufacturing a solar cell module, the sheet-shaped resin members are formed to have substantially flat and smooth surfaces. As a consequence, an interface between the first and second sealing members is also substantially flat and smooth.
Here, moisture that enters the solar cell module tends to gather at the interface between the first sealing member and the second sealing member having mutually different properties. When the interface between the first sealing member and the second sealing member is substantially flat and smooth, the moisture that gathers at the interface tends to spread and to enter a core portion of the solar cell module. Accordingly, the moisture may reach the plurality of solar cells included in the solar cell string and thereby degrades a power generation capacity of the solar cell module.